Measuring effects of insulation renewal on heating energy and indoor thermal environment in urban residence of hot-summer/cold-winter region, China

Optimizing thermal insulation in residential buildings is crucial for energy efficiency, especially in Hot Summer and Cold Winter (HSCW) region. Current research often neglects retrofitting and real-life measurements, relying instead on simulations. This study conducted insulation retrofitting on a Chengdu high-rise residential unit, focusing on the flexible heating habits locally. The insulation renewal work involved transforming the thermal insulation structure by adding insulation to all internal surfaces of the rooms' opaque structure, including external walls, internal walls, ceilings, and floors. Experiments based on residents' routines quantified energy savings and improved indoor thermal conditions under intermittent heating. Results showed a significant decrease in daily heating energy consumption by 45.10 % on average, with a maximum of 55.53 %. The retrofitted room's energy-saving rate stabilized between 50 % and 55 % after the second hour. Indoor temperatures in the retrofitted bedroom increased by 0.7 °C on average and up to 1.4 °C. Raising the heating set temperature by 2 °C resulted in a 1.1 °C increase in the retrofitted room, higher than in the non-retrofitted one. These findings provide practical insights for renovating existing residences to achieve energy efficiency in the HSCW region.